Only a few of the plurality of prior-art patch plugs are suitable for high-temperature applications, in which the plugs are exposed to a thermal load of 120° C. and higher. Especially problematic is the use of plastic inserts that are often used at lower temperatures to electrically insulate the outer surface of the plug and the individual poles against one another and to fix them to one another in a preset position.
High-temperature plugs in which a connection is established for every individual pole between a contact element and a conductor and the corresponding connection is then surrounded, especially after the plug thus produced has been combined with a counterplug, with a housing made of PEEK or heat-shrinkable sleeve, which said housing is coordinated with the conductor cross section and the external diameter of the individual conductor and is crimped with same and is thus thermally and electrically insulated, are known. High-temperature plugs of this type are available, e.g., from Electrolux under the name “high-temperature plug-in connection HTC.”
The drawback of this embodiment is that the manufacture of a plug-in connection is associated with a relatively great effort. Furthermore, the space requirement is relatively high, especially for multipole high-temperature plug-in connections, which are based on these plugs.
There is also a need for a high-temperature plug in the cleaning of plastic spray nozzles extrusion coated or sprayed over with plastic, on which a heating element is mounted, by furnace application at temperatures of, for example, higher than 300° C.